Bacteriological oven or incubator.



No. 789,237. PATENTED MAY 9, 1905. G. B. SKINNER.

BACTERIOLOGIUAL OVEN OR INGUBATOR.

APPLICATION FILED JUNE 30, 1904 WITNESSES: P IZ VENTO R a @W' m 944 M v 33 g TTORNEY Patented May 9, 1905.

UNITED STATES PATENT OFFICE.

CHARLES EDlVARD SKINNER, OF ILKINSBURG, PENNSYLVANIA.

BACTERIOLOGICAL OVEN OR INCUBATOR.

SPECIFICATION forming part of Letters Patent No. 789,287, dated May 9, 1905.

Application filed June 30, 1904. Serial No. 214,831.

To all whom, it nury concern:

Be it known that 1, CHARLES EDWARD SKIN- NER, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Bacteriological Ovens or Incubators, of which the following is a specification.

My invention relates to bacteriological ovens or incubators; and it has for its object to provide an apparatus of this character which shall be inexpensively heated by such means and in such manner that the temperature will be automatically regulated and maintained sub stantially uniform throughout any desired period of operation.

In the accompanying drawings, Figure 1 is a sectional view of an apparatus constructed in accordance with my invention. Fig. 2 is a diagram of the electric circuits of the heating and regulating apparatus, and Fig. 3 is a sec tional view of the thermostatic portion of the regulator. Fig. 1 is a sectional view of one corner of an oven having a heating-coil located in the water-jacket.

The oven, which may be of any suitable form and have any desired structural characteristics, is here indicated as comprising a chamber 1, having a plurality of shelves 2 therein, and a chamber 3, having suitable heaters located therein,'here shown as a plurality of incandescent lamps 1. The chamber 1 is here shown as having sheet-metal walls 5 and as surrounded by a shell 6, between which and the walls 5 is a chamber filled with liquid 7. Surrounding the shell 6 is an outer shell 8, between which and the shell 6 is an air-space 9, the air in the space 9 on account of its poor conductivity of heat serving to aid in maintaining a constant temperature in the chamber 1.

The structure above described is mounted upon a base portion 10 in the form of a box divided by a horizontal partition 10 into two compartments 10 and 10. The upper compartment 10" contains a circuit making and breaking device 11, and the lower compartment 10" contains a suitable battery 12.

The circuit making and breaking device 11 comprises a magnet 13 and an arm 14:, pivoted at one end to a bracket or standard 15 and having at that end an armature 16. Projecting from the armature end of the arm 14 is a screw-rod 1 1, on which is mounted a nut 17 of suiiicient weight to overbalance the arm 14. The other end of the arm 14: is provided with a U-shaped contact-terminal 18, the ends oi which project into mercury-ciuis 19 when lowered by the action of the magnet 13 upon the armature 16.

Mounted upon the top of the outside casing 8 is a standard 20, having an arm or plate 21, from which a perforated tube 22 projects downward into the liquid 7 between the shells 5 and 6 nearly to the bottom of the said liquid or to such point therein as may be desirable.

Fastened to a block 23 in the lower end of the tube 22 is the lower end of a thermostatic bar 2 1, composed of two strips of different metals having different degrees of expansibility under the action of heat. Attached to the upper end of the composite bar 2 1 is a block 25, in which is mounted a screw 26, having at one end a disk 27 and at its other end a contact-pin 2S. Beneath the disk 27 is a block or plate 29, one or both of these parts having suitable scale-marks, so that the degree of adjustment of the pin 28, which is eflected by turning the disk 27 and the screw 26, may be indicated. Supported upon the bar or plate 21 is a bracket 30, which is insulated from the pipe 22 by a suitable insulating-block 81, and in the bracket 30 is mounted a tube 32, through which projects a pin 83, one end of which is normally in contact with the end of pin 28. The opposite end of the pin 38 is screwthreaded and provided with an adjusting-nut 3 1, and within the tube the pin is provided with a collar 35, against which bears one end of a small coiled spring 36, this spring being provided in order that the pin 33 may yield, and thus permit of deflection of the composite bar 2 1 in that direction to such extent as may be desired.

The electrical circuits of the apparatus are shown in Fig. 2. The current for the lamps 1 is derived from mains 37 and is normally supplied from one of the mains through a branch conductor 38, the mercury-cups 19 and contact-terminals 18, suitable switches 39, and

the lamps 4, back to the other main 37 by conductor 10.

In case the heat rises above the desired temperature the bar 24 will be deflected from its central or normal position, so as to move the pin 28 away from the adjacent end ot-the pin 33, and thus open the circuit of the battery 12. The magnet 13 being thus deenergized, the Weight 17 will tilt the arm let on its pivot, and thus raise the terminal 18 from the mercury-cups 19 and interrupt the lamp-circuit. As soon as the temperature falls to the desired degree the battery-circuit will be again closed by the engagement of the pin 28 with the pin 33, and the magnet 13 will thereupon act to close the lamp-circuit. v

Other suitable arrangements of circuits and controlling devices may be employed, i't' desired.

This apparatus is very sensitive and certain in its operation and is so readily susceptible of regulation by means of variations in the heat that any desired uniform temperature may be maintained by regulating the number of lamps employed and by adjusting the thermostatic device so that it will act in accordance with the degree of heat desired.

The form and arrangement of the several elements of my invention may obviously be varied from What is shown, one variation which may be specifically mentioned being illustrated in Fig. at. As here shown, a suitable resistance device, such as a coil of wire 41, is substituted for the incandescent lamps and is located in the Water jacket. This heater may be of any suitable form and may be located in any desired portion of the jacket.

1 claim as my invention 1. In a heating apparatus, the combination with a chamber and a water-jacket surrounding the same, of an electric circuit having resistance devices located below said Waterjacket, of a making and breaking device for said circuit, and a controlling means for said making and breaking device comprising an electromagnet, a circuit therefor and a thermo- 1 static make-and-break device projecting into the water-jacket which surrounds the heatingchamber.

2. A heatingapparatuscomprising achamher, a water-jacket surrounding the same, an electric circuit having resistance devices located beneath said chamber and jacket, a makeand-break device for said circuit, and a separate controlling-circuit for said make-andbreak device having a thermostatic controller that projects into the water-jacket surrounding the said chamber.

3. The combination with a chamber and a Water-jacket surrounding the same, of an electric circuit having resistance devices located in proximity to said jacket and having a makeand-break device, an auxiliary controllingcircuit comprising an electromagnet, a source of current and a thermostatic make-and-brcak device that projects into the water-jacket and an air-chamber surrounding said jacket.

4. The combination with a chamber having a water-jacket and an electric circuit having resistance devices located beneath said jacket, of a make-and-break device for said circuit and a controlling-circuit for said make-andbreak device having a tllermostaticallyregu lated make-and-break device the thermostatic member of which projects into the waterjacketand having relatively adjustable contact-pieces.

5. The combination with a chamber and an electric circuit having one or more resistance devices so disposed as to heat said chamber, and a make-and-break device, of a controllingcircuit for said make-and-break device having an opening and closing means comprising a thermostatic member that is subjected to the heat in said chamber.

In testimony whereof I have hereunto subscribed my name this 22d day of June, 1901.

CHARLES EDWARD SKlNNlllt. 'itnesses:

, U. L. BicLcnaR, BIRNEY HINus. 

